Highly sensitive and selective electrochemical sensor based on porous graphitic carbon nitride/CoMn2O4 nanocomposite toward heavy metal ions

The combination of semiconductors and binary transition metal oxides has drawn growing interest in terms of their enhanced electrochemical analysis performance in electrochemical sensing. A new type of highly sensitive and selective sensor was designed and developed by constructing a nanocomposite system of porous graphitic carbon nitride and CoMn2O4 (pg-C3N4/CoMn2O4) to detect heavy metal ions of Cd(II) and Pb(II). The morphological and structural characteristics of pg-C3N4/CoMn2O4 nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The optimized current responses obtained through the square wave anodic stripping voltammetry (SWASV) of Cd(II) and Pb(II) increased linearly with their concentration in wide linear dynamic ranges of 0.5-7.0 mu M and 0.2-4.4 mu M, respectively, as well as low detection limits of 0.021 mu M for Cd(II) and 0.014 mu M for Pb(II). Further, the proposed sensor was successfully applied for the determination of Cd (II) in actual water samples accomplished with the value of recoveries ranging from 93.0%-106.0%. In addition, good anti-interference, favorable reproducibility, excellent stability and repeatability of the sensor enable it feasible for the detection of heavy metal ions.